Am i the only one!?

Well here it is, my name is kaytlynn I'm going to be 20 the 10th of this month, working, etc. I've been with an amazing guy for two years this April were engaged, living together for month everything seems to be falling into place but at the same token I feel like we're missing something, like something I wanted ever since we started dating we talked about it none stop, we want to have a baby, but everyone is telling us to wait were to young, etc. But I feel like I'm missing a HUGE part of me. I just wanna know if anyone else is in this situation? If so please give me advice on what people are telling you, I know we're adults, but a little advice will help!